Gliederung

Objective: This clinical study is aimed to improve the survival and QOL of patients with malignant brain tumors, especially high grade gliomas.

From 1999 to 2003, 12 patients with histologically proven malignant gliomas were treated by boron neutron capture therapy (BNCT) using sodium borocaptate (BSH) or boronophenylalanine (BPA) or both combined. The patients were irradiated at the research reactor of the Japan Atomiic Energy research Institute (JAERI) in a single session. The irradiation was performed under craniotomy in the early phase using thermal neutrons and external irradiation by applying epi-thermal neutrons in advanced phase. In the latter phase, patients with recurrent tumors with prior full dose radiation therapy were enrolled in the study.

The median survival time (MST) in glioblastoma patients was 23.7 months(M) and 33.3 M in grade III malignant gliomas. There was 4 patients with visible residual tumors and all patients showed complete response or partial response. The failure pattern was outside the radiation field and including seeding of the tumors except for one patient with local recurrence. The recurrent cases showed tumor shrinkage within several weeks.

BNCT revealed a favorable clinical outcome with a single fraction irradiation in selected cases. The use of an epi-thermal neutron beam and treatment planning system made an external irradiation possilbe which is less invasive for the patients. The long-term results of external beam irradiation have to be evaluated with more long-term observation. A prospective study is warranted to prove the efficacy of the usefulness of BNCT in the future.